Degradation of lignocellulosic biomass is a process used in many branches of industry, mainly in the production of biofuels. Various kinds of energy crops are used to produce high-quality biofuels, such as biogas (biomethane) or bioethanol. The key step, limiting the production of the aforementioned biofuels, is the process of hydrolysis of lignocellulosic material to simpler carbohydrates. In the production of bioethanol, hydrolysis of the plant matter leads to the formation of simple sugars, which undergo alcoholic fermentation. On the other hand, in the production of biogas, plant substrates undergo hydrolysis and then the processes of acidogenesis, acetogenesis and finally methanogenesis. Too slow rate of hydrolysis of lignocellulose leads to stalling of the entire process of degradation of plant biomass and, consequently to the reduction of the efficiency of the fermentation process. On the other hand, excessive hydrolysis of plant substrates can lead to too great an accumulation of intermediate products, which may contribute to system overload and deceleration (or complete inhibition) of the activity of microorganisms carrying out the final stages of biofuel production. The efficiency of hydrolysis and plant biomass degradation processes is dependent on the presence and activity of cellulolytic microorganisms. In agricultural biogas plants and in wastewater treatment plant digesters, the hydrolysis process is dependent on the presence of cellulolytic microorganisms in the input material (i.a. slurry, manure or sewage sludge). If the input material used is poor in cellulolytic microflora, the hydrolysis process will be slow and unstable. Stabilization of an appropriate microflora can take up to several months, which, obviously has a direct impact on the efficiency of the process and on economic benefits.
Currently, the biogas market is trying to respond to the problems caused by the unstable activity of microbial consortia. A great need for a biologically active preparation, which may comprise a stable and well-controlled consortium of microorganisms for the hydrolysis and degradation of lignocellulosic biomass, is observed. Due to the unstable activity and the lack of the ability to control plant biomass degradation, nearly 20% of biogas plants close their operation within the first two years on the market. Preparations that would enable efficient hydrolysis and operation of the process in a controlled manner are sought. Preparations for increasing the viability and efficiency of the microorganisms involved in the production of biogas in the methane fermentation process as well as their revival are also sought.
Microbiological preparations (i.a. produced by German and Danish companies), are available on the biogas market, typically being used for faster ensilage of corn, grass or other batch plants. They are derived from preparations that has been used for preparation of animal feeds for years. Silasil Energy. C, Jbs progas, or AntaSil BG comprise a mixture of bacteria from the genus Lactobacillus, whose presence in the silage improves the content of lactic acid, which is a substrate for the microorganisms responsible for methane fermentation. According to the manufacturers' advertising, through such activity, the efficiency of obtaining methane increases by approx. 5%.
In the group of preparations dispensed directly into digesters, mainly mineral supplements of methane fermentation are found. Products such as IPUSmeth-Max are mixtures of micronutrients and substances buffering the resulting ammonia, too high concentrations of which is a methanogenesis inhibitor. According to the manufacturer, its use can bring up to 10% increase of the efficiency of methane production, but it requires constant expenses to purchase the preparation, the dosage of which should be almost daily. In this group, one of the very few products containing microorganisms is AntaFerm BG, consisting of both cultures of microorganisms and trace elements. In the case of using the above preparations, investments of 25-42 euros per 30 tons of input are required. These are expensive solutions, which do not always give a radical improvement in the functioning of the biogas plant.
Preparations intended directly for plant biomass hydrolysis are also known. These are enzymatic preparations which are stable, but they are usually specific for a particular pool of substrates, because they are derived from one strain (typically from fungi). Moreover, such preparations are expensive, because they must be systematically and regularly added to the working biogas plant. Such preparations include, among others, Celuferm (Eurozyme) and BG Max (Novozymes).
Currently preparations for the hydrolysis of lignocellulosic biomass, which: (i) after a single addition, would ensure long-term and stable operation of the biogas plant, (ii) would be relatively inexpensive, (iii) would have a broad spectrum of activity, would be universal and resistant to the changing environmental conditions, are sought. In summary, preparations employing a bacterial biomass, capable of propagation using the utilized lignocellulosic material are sought. Thus, preparations, which will increase the viability of methanogenic microorganisms and eventually support the efficiency of gas production by methanogenic microorganisms using lignocellulosic material are also sought.
Citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention.